I've been lurking on this conversation, and I am again left with the impression that the underlying shared memory configuration based on sharing a file is flawed. Why not use a System V shared memory segment without a backing file as I described in ticket #1320?
On Mon, Mar 30, 2009 at 1:34 PM, George Bosilca <bosi...@eecs.utk.edu> wrote: > Then it looks like the safest solution is the use either ftruncate or the > lseek method and then touch the first byte of all memory pages. > Unfortunately, I see two problems with this. First, there is a clear > performance hit on the startup time. And second, we will have to find a > pretty smart way to do this or we will completely break the memory affinity > stuff. > > george. > > On Mar 30, 2009, at 13:24 , Iain Bason wrote: > >> >> On Mar 30, 2009, at 12:05 PM, Jeff Squyres wrote: >> >>> But don't we need the whole area to be zero filled? >> >> It will be zero-filled on demand using the lseek/touch method. However, >> the OS may not reserve space for the skipped pages or disk blocks. Thus one >> could still get out of memory or file system full errors at arbitrary >> points. Presumably one could also get segfaults from an mmap'ed segment >> whose pages couldn't be allocated when the demand came. >> >> Iain >> >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/devel > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel > -- Tim Mattox, Ph.D. - http://homepage.mac.com/tmattox/ tmat...@gmail.com || timat...@open-mpi.org I'm a bright... http://www.the-brights.net/
